in that case

I book it.

私は別の道を通って行きます

There are seats free in the afternoon too, and I book it.

この道は混んでいます、私は別の道を通って行きます

There are seats free in the afternoon too; in that case I book it.

この道は混んでいます、それなら私は別の道を通って行きます

There are seats free in the afternoon too; in that case I book it now.

この道は混んでいます、それなら私は今別の道を通って行きます

There are seats free in the afternoon too; in that case I book it on my phone now.

この道は混んでいます、それなら私は今会社まで別の道を通って行きます